With rapid development of high-speed mobile Internet technologies, various wireless broadband access technologies emerge one after another, for example, a Long Term Evolution (LTE) system, and an LTE-Advanced (LTE-A) system. In these systems, using a same time and frequency resource, data can only be received or sent between a base station and a user equipment, but cannot be received and sent simultaneously. For example, in a frequency division duplex (FDD) system, a base station uses different frequency resources to separately send data to a user and receive data. With evolution of the wireless broadband access technologies, in order to further improve system capacity using a limited spectrum resource, a full-duplex communication method is discussed and put forward at present, which supports simultaneous data receiving and sending between devices using a same time and frequency resource, that is, on a same carrier. A device that uses this sending manner may be referred to as a full-duplex device.
However, because the full-duplex device simultaneously receives and sends data on the same carrier, the following problem may occur: a reference signal used for demodulating data is sent while data is sent, and interference occurs between the sent reference signal and a received reference signal. Consequently, correct receiving of the reference signal is affected and correct demodulation of the data cannot be ensured.